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Aik Sian Tan Jaymeer Singh Nurul Syafiqah Rezali Musthahimah Muhamad Nik Nur Syazni Nik Mohamed Kamal Yvan Six Mohamad Nurul Azmi 《Molecules (Basel, Switzerland)》2022,27(17)
The Heck cross-coupling reaction is a well-established chemical tool for the synthesis of unsaturated compounds by formation of a new C-C bond. In this study, 1,3-diarylpropene derivatives, designed as structural analogues of stilbenoids and dihydrostilbenoids, were synthesised by the palladium-catalysed reactions of 2-amidoiodobenzene derivatives with either estragole or eugenol. The products were obtained with high (E) stereoselectivity but as two regioisomers. The ratios of isomers were found to be dependent on the nature of the allylbenzene partner and were rationalised by electronic effects exercising a determining influence in the β-hydride elimination step. In addition, the cytotoxic effects of all the Heck reaction products were evaluated against MCF-7 and MDA-MB-231 human breast cancer cells, with unpromising results. Among all, compound 7d exhibited weak cytotoxic activity towards MCF-7 cell lines with IC50 values of 47.92 µM in comparison with tamoxifen and was considered to have general toxicity (SI value < 2). 相似文献
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Revathy Deivasigamani Nur Shahira Abdul Nasir Mohd Ambri Mohamed Muhamad Ramdzan Buyong 《Electrophoresis》2022,43(4):609-620
This article describes a dielectrophoresis (DEP)-based simulation and experimental study of human epidermal keratinocyte (HEK) cells for wounded skin cell migration toward rapid epithelialization. MyDEP is a standalone software designed specifically to study dielectric particles and cell response to an alternating current (AC) electric field. This method demonstrated that negative dielectrophoresis (NDEP) occurs in HEK cells at a wide frequency range in highly conductive medium. The finite element method was used to characterize particle trajectory based on DEP and drag force. The performance of the system was assessed using HEK cells in a highly conductive EpiLife suspending medium. The DEP experiment was performed by applying sinusoidal wave AC potential at the peak-to-peak voltage of 10 V in a tapered aluminum microelectrode array from 100 kHz to 1 MHz. We experimentally observed the occurrence of NDEP, which attracted HEK cells toward the local electric field minima in the region of interest. The DIPP-MotionV software was used to track cell migration in the prerecorded video via an automatic marker and estimate the average speed and acceleration of the cells. The results showed that HEK cell migration was accomplished approximately at 6.43 μm/s at 100 kHz with 10 V, and FDEP caused the cells to migrate and align at the target position, which resulted in faster wound closures because of the application of an electric field frequency to HEK cells in random locations. 相似文献
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Junaidi Junaidi Muhamad Wahyudi Saputra Roniyus Marjunus Simon Sembiring Sutopo Hadi 《Molecules (Basel, Switzerland)》2021,26(8)
This study aims to determine the effect of fast cooling (quenching) on thermal properties, mechanical strength, morphology and size of the AgNWs. The synthesis of AgNWs was carried out at three different quenching-medium temperatures as follows: at 27 °C (ambient temperature), 0 °C (on ice), and −80 °C (in dry ice) using the polyol method at 130 °C. Furthermore, the AgNWs were sonified for 45 min to determine their mechanical strength. Scanning electron microscopy analysis showed that the quenched AgNWs had decreased significantly; at 27 °C, the AgNWs experienced a change in length from (40 ± 10) to (21 ± 6) µm, at 0 °C from (37 ± 8) to (24 ± 8) µm, and at −80 °C from (34 ± 9) to (29 ± 1) µm. The opposite occurred for their diameter with an increased quenching temperature: at 27 °C from (200 ± 10) to (210 ± 10) nm, at 0 °C from (224 ± 4) to (239 ± 8) nm, and at −80 °C from (253 ± 6) to (270 ± 10) nm. The lower the temperature of the quenching medium, the shorter the length and the higher the mechanical strength of AgNWs. The UV-Vis spectra of the AgNWs showed peak absorbances at 350 and 411 to 425 nm. Thermogravimetric analysis showed that AgNWs quenched at −80 °C have better thermal stability as their mass loss was only 2.88%, while at the quenching temperatures of 27 °C and 0 °C the mass loss was of 8.73% and 4.17%, respectively. The resulting AgNWs will then be applied to manufacture transparent conductive electrodes (TCEs) for optoelectronic applications. 相似文献
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Syahmi AR Vijayarathna S Sasidharan S Latha LY Kwan YP Lau YL Shin LN Chen Y 《Molecules (Basel, Switzerland)》2010,15(11):8111-8121
Elaeis guineensis (Arecaceae) is widely used in West African traditional medicine for treating various ailments. An evaluation on the toxicity of extracts of this plant is crucial to support the therapeutic claims. The acute oral toxicity and brine shrimp lethality of a methanolic extract of this plant was tested. Oral administration of crude extract at the highest dose of 5,000 mg/kg resulted in no mortalities or evidence of adverse effects, implying that E. guineensis is nontoxic. Normal behavioral pattern, clinical signs and histology of vital organs confirm this evidence. The E. guineensis extracts screened for toxicity against brine shrimp had 50% lethal concentration (LC??) values of more than 1.0 mg/mL (9.00 and 3.87 mg/mL, at 6 and 24 h, respectively), confirming that the extract was not toxic. Maximum mortalities occurred at 100 mg/mL concentration while the least mortalities happened to be at 0.195 mg/mL concentration. The results of both tests confirm that E. guineensis is nontoxic and hence safe for commercial utilization. 相似文献
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Zulhelmi Alif Abdul Halim Muhamad Azizi Mat Yajid Mohd Hasbullah Idris Halimaton Hamdan 《Journal of Dispersion Science and Technology》2018,39(8):1093-1101
The thermal-mechanical properties of unsaturated polyester (UP) composite were enhanced by the dispersion of silica aerogel (SA) with preserved pores. Low-cost SA was prepared from rice husk via the sol-gel process and ambient pressure drying. A new method was proposed to encapsulate the hydrophobic aerogel surface pores with hydrophilic polyvinyl alcohol (PVA) film using the fluidized-bed coating process. The dispersion of PVA-coated aerogel with preserved pores in the polyester matrix resulted in an increase of specific compressive strength (44.1?MPa?·?cm3?g?1), thermal insulation (0.23?W?m?1?K?1), and thermal stability (Tonset?=?310°C), but decreased the glass transition temperature (Tg?=?260°C). 相似文献
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Habu Tela Abba Wan Muhamad Saridan Wan Hassan Muneer Aziz Saleh Abubakar Sadiq Aliyu Ahmad Termizi Ramli Hassan Abdulsalam 《Isotopes in environmental and health studies》2018,54(5):522-534
The Jos Plateau has been reported to have elevated levels of natural background radiation. A few earlier studies have measured the levels of natural radioactivity for specific locations in the area. Our interest is to investigate how geology of the study area influences the activity concentrations of natural radionuclides. Thus, the activity concentrations of terrestrial radionuclides in soil samples collected across the geological formations of the Jos Plateau were determined by gamma spectrometry technique. The mean activity concentrations of 226Ra, 232Th and 40K were found to exceed their corresponding world reference values of 35, 40 and 400?Bq?kg?1, respectively. Data were compared using statistical methods, analysis of variance (ANOVA) and post hoc tests. The results revealed in some instances significant influences of geological types on the activity concentrations in the area. The spatial distribution maps of activity concentrations of 226Ra, 232Th and 40K were geostatistically interpolated by ordinary Kriging method using ArcGIS software. 相似文献
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T Takeguchi T Yamanaka K Asakura EN Muhamad K Uosaki W Ueda 《Journal of the American Chemical Society》2012,134(35):14508-14512
A randomly mixed monodispersed nanosized Pt-Ru catalyst, an ultimate catalyst for CO oxidation reaction, was prepared by the rapid quenching method. The mechanism of CO oxidation reaction on the Pt-Ru anode catalyst was elucidated by investigating the relation between the rate of CO oxidation reaction and the current density. The rate of CO oxidation reaction increased with an increase in unoccupied sites kinetically formed by hydrogen oxidation reaction, and the rate was independent of anode potential. Results of extended X-ray absorption fine structure spectroscopy showed the combination of N(Pt-Ru)/(N(Pt-Ru) + N(Pt-Pt)) ? M(Ru)/(M(Pt) + M(Ru)) and N(Ru-Pt)/(N(Ru-Pt) + N(Ru-Ru)) ? M(Pt)/(M(Ru) + M(Pt)), where N(Pt-Ru)(N(Ru-Pt)), N(Pt-Pt)(N(Ru-Ru)), M(Pt), and M(Ru) are the coordination numbers from Pt(Ru) to Ru(Pt) and Pt (Ru) to Pt (Ru) and the molar ratios of Pt and Ru, respectively. This indicates that Pt and Ru were mixed with a completely random distribution. A high-entropy state of dispersion of Pt and Ru could be maintained by rapid quenching from a high temperature. It is concluded that a nonelectrochemical shift reaction on a randomly mixed Pt-Ru catalyst is important to enhance the efficiency of residential fuel cell systems under operation conditions. 相似文献
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Hashim NM Rahmani M Ee GC Sukari MA Yahayu M Amin MA Ali AM Go R 《Molecules (Basel, Switzerland)》2012,17(5):6071-6082
One of the most promising plants in biological screening test results of thirteen Artocarpus species was Artocarpus obtusus FM Jarrett and detailed phytochemical investigation of powdered dried bark of the plant has led to the isolation and identification of three xanthones; pyranocycloartobiloxanthone A (1), dihydroartoindonesianin C (2) and pyranocycloartobiloxanthone B (3). These compounds were screened for antioxidant, antimicrobial and tyrosinase inhibitory activities. Pyranocycloartobiloxanthone A (1) exhibited a strong free radical scavenger towards DPPH free radicals with IC50 value of 2 μg/mL with prominent discoloration observed in comparison with standard ascorbic acid, α-tocopherol and quercetin, The compound also exhibited antibacterial activity against methicillin resistant Staphylococcus aureus (ATCC3359) and Bacillus subtilis (clinically isolated) with inhibition zone of 20 and 12 mm, respectively. However the other two xanthones were found to be inactive. For the tyrosinase inhibitory activity, again compound (1) displayed strong activity comparable with the standard kojic acid. 相似文献
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C. F. Mok F. Muhamad N. A. Abu Osman Ramesh Singh 《International Journal of Polymer Analysis and Characterization》2017,22(4):294-304
Poly(vinyl alcohol)-α-chitin composite films reinforced by oil palm empty fruit bunch fiber-derived nanocellulose were prepared by casting technique. Fourier transform infrared spectroscopy analysis revealed partial miscibility between chitin and poly(vinyl alcohol) through hydrogen bonding, as supported by differential scanning calorimetry and field emission scanning electron microscopy. Tensile strength of the poly(vinyl alcohol)/chitin films increased with α-chitin content varied from 10 to 30?wt%, which was from 29.06 to 39.27?MPa. With the addition of 1?wt% nanocellulose, a maximum improvement of 57.64 and 50.66% in terms of tensile strength and Young’s modulus was achieved, respectively. 相似文献